Vented furring strip

ABSTRACT

A wall system for a structure including elongate furring strips having a multiplicity of transversely oriented air passages. The elongate furring strips are arranged on a first envelope layer of a wall and covered with a second envelope layer. The furring strips space the first and second envelope layers apart, forming a plurality of enclosed cavities or air spaces. The cavities are in fluid communication with each other through the air passages in the furring strips, and may be in fluid communication with the outside atmosphere. Air is thusly enabled to circulate from the outdoors through substantially all portions of the cavities, promoting drying of the first and second envelope layers, which may be sheathing and finish siding.

RELATED APPLICATIONS

The application is a continuation of co-pending prior application Ser.No. 11/052,652, filed Feb. 7, 2005, entitled VENTED FURRING STRIP, whichis a continuation of application Ser. No. 10/706,606, filed Nov. 12,2003, entitled VENTED FURRING STRIP, now U.S. Pat. No. 6,938,383, whichin turn claims priority under 35 U.S.C. § 119(e) from ProvisionalApplication No. 60/426,730, filed Nov. 15, 2002, entitled VENTED FURRINGSTRIPS. All of the referenced related applications are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The invention relates to wall systems of structures, and morespecifically to devices and methods for ventilating wall systems ofstructures.

BACKGROUND OF THE INVENTION

The exterior walls of modern buildings, especially residential typestructures, often include a frame, covered on the exterior side with asheathing material. Wood sheet products, such as CDX plywood or orientedstrand board (OSB), are often used as the sheathing material. Finishsiding material is applied over the sheathing for weather and physicaldamage protection and to give the structure a more attractiveappearance.

The finish siding used in construction is usually not completelyresistant to water and water vapor infiltration. Water fromprecipitation may migrate or leak through finish siding. Moreover,moisture-laden air may permeate the finish siding layer during periodsof warmer outdoor temperature. When the outdoor temperature drops, themoisture may condense from the air as liquid water onto the surfaces ofthe finish siding and sheathing, even forming ice at lower temperatures.This condensation may penetrate and saturate porous finish sidingmaterial or sheathing material.

Water in any form remaining for extended periods within, or on surfacesof, the finish siding or sheathing materials may have deleteriouseffects for a structure and its inhabitants. Porous materials mayundergo temporary or permanent dimensional changes from waterinfiltration, including warping and swelling, and subsequent shrinkingas the material dries. These dimensional changes can loosen connectionsbetween building components, and open seams or cracks, leading to morewater infiltration. Organic materials, such as sheathing made from woodproducts, may rot or become a location for mold and mildew growth.Rotting or other such deterioration may compromise the structuralintegrity of the building. In addition, mold or mold spores maypenetrate into the interior of the structure, causing adverse healthconsequents for occupants.

One or more layers of building paper are typically applied oversheathing material to retard water infiltration. Usually, this buildingpaper is asphalt impregnated felt material or spun-bonded polyolefinsheeting. Asphalt felt material may become saturated with water ifexposed to moisture over a long period, however, in turn causingmoisture in the sheathing. The polyolefin materials, on the other hand,are designed to pass moisture vapor, while preventing the passage ofbulk water. Without the circulation of dryer air, however, any condensedwater present between the polyolefin material and the sheathing may notdry out and the sheathing is consequently exposed to moisture over along period.

An air space is sometimes created between the finish siding and thebuilding paper covered sheathing material in order to provide a spacefor air circulation. Typically, an air space is created by firstaffixing furring strips made from solid material to the sheathing andthen affixing the siding to the furring strips. One or more openings tothe exterior are provided leading to the space to permit aircirculation. Drier air from the exterior circulating within this spacemay evaporate and absorb any bulk moisture present on the surfaces ofthe building paper, sheathing, or finish siding.

It is, however, necessary that ventilation air freely circulate intothis air space in order that a continuous supply of dry air is availableto replace the moisture-laden air resulting from the evaporationprocess. Due to the very confined nature of this air space, and the needto provide a continuous finish siding layer to minimize water leakage tothe extent possible, adequate ventilation of this space has proven to bedifficult to achieve. For instance, the solid furring strips themselvesmay block or restrict air circulation.

What is needed is an apparatus, system, and method for effectivelyventilating a space provided in the wall system of a structure thatovercomes the aforementioned problems.

SUMMARY OF THE INVENTION

The present invention is an apparatus, system, and method forventilating a space provided in the wall system of a structure thatovercomes the aforementioned problems. The invention includes a wallsystem for a structure including elongate furring strips having amultiplicity of transversely oriented air passages. The elongate furringstrips are arranged on a first envelope layer of a wall and covered witha second envelope layer. The furring strips space the first and secondenvelope layers apart, forming a plurality of enclosed cavities or airspaces. The cavities are in fluid communication with each other throughthe air passages in the furring strips, and may be in fluidcommunication with the outside atmosphere. Air is thusly enabled tocirculate from the outdoors through substantially all portions of thecavities, promoting drying of the first and second envelope layers,which may be sheathing and finish siding. In addition, furring stripsaccording to the invention may be positioned at the bottom edge of thewall assembly so that any liquid bulk water penetrating the siding isenabled to drain out.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of the furring strip ofthe invention;

FIG. 2 is an end view of the furring strip of FIG. 1;

FIG. 3 is a fragmentary, cross-sectional view of a first embodiment oftwo portions of the furring strip of FIG. 1;

FIG. 4 is a fragmentary, cross-sectional view of a second embodiment ofone layer of the furring strip of FIG. 1;

FIG. 5 is a fragmentary, cross-sectional view of a third embodiment offour portions of the furring strip of FIG. 1;

FIG. 6 is a plan view of a sheet of convoluted material suitable forforming the furring strip of FIG. 1;

FIG. 7 is a side plan view of the sheet of FIG. 6 being foldablyassembled into the furring strip of FIG. 1 after layers have beendefined therein;

FIG. 8 is a perspective, partial cut away view of a structure showing anapplication of the present invention; and

FIG. 9 is a cross-sectional view of a wall system according to thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An exemplary furring strip 10 is depicted in FIGS. 1 and 2. Furringstrip 10 generally includes one or more layers 12 and may present alongitudinal axis 14. Layers 12 are described below and generally servetwo functions. The first function is to allow water to draintherethrough. The second is to enable air exchange. These complimentaryfunctions promote drainage, prevent water condensation, and promotedrying of the interstitial space between components of exterior walls ofa structure in which the furring strip 10 is used. While one or morelayers 12 are contemplated to be within the scope of this invention, ifa plurality of layers 12 are present, these layers may be stacked andfixed to each other by such means as stitching 16. However, otherfastening means which may be used include hot air welding (or otherfastening means using thermal energy), ultrasonic welding, infraredbonding, staples, glue, or other methods known to the art. The structureof furring strip 10 may be generally similar to the roof battendisclosed in U.S. Pat. No. 6,357,193, a copy of which is hereby fullyincorporated herein by reference.

One embodiment of layer 12 is depicted in FIG. 3. Layer 12 has twoportions 18, 20. Each portion 18, 20 includes planar plies 22 and 24 andconvoluted ply 26. Convoluted ply 26 is disposed between and bonded to(or otherwise cooperates with) planar plies 22 and 24 to define amultiplicity of air channels 28 therebetween. Channels 28 extendgenerally perpendicularly, or otherwise generally transversely, tolongitudinal axis 14 of furring strip 10.

Another embodiment of layer 12 is depicted in FIG. 4. Layer 12 includesplanar plies 30 and 32 and second ply 34. Second ply 34 includes amultiplicity of cross-plies 36. Cross-plies 36 extend generallyperpendicular (or otherwise transversely) between planar plies 30 and32. Thus, planar plies 30 and 32 and second ply 34 cooperate to define amultiplicity of air channels 28 therebetween.

Referring to FIG. 5, yet another embodiment of layer 12 is depictedgenerally. Layer 12 has four portions 40, each generally includingplanar ply 42 and convoluted ply 44. Planar and convoluted plies 42 and44 are bonded to (or otherwise cooperate with) each other to define amultiplicity of air channels 28 therebetween. Portions 40 may be stackedsuch that convoluted plies 44 abut, thereby defining anothermultiplicity of air channels 28 therebetween.

These embodiments of layer 12 include a corrugated plastic (resin)material with a nominal weight appropriate for the structure, and oftenbetween a range of about 140 and 160 pounds per thousand square feet.One nominal weight may be about 150 pounds per thousand square feet. Theplastic resin may have a 4.0 to 4.5-millimeter profile. The plasticresin may further include an about 4.0 (.+−.0.2) millimeter profile. Theplastic material may still further be black and include ultraviolet (UV)inhibitors to enable the plastic resin to withstand extended exposure todirect UV light. The plastic resin may include a high-density,polyethylene, corrugated, plastic resin with a brittleness temperatureof about −103.0 degrees F., a deflection temperature of about +162.0degrees F. at 66 pounds per square inch, a bum rate of about 2.5 inchesper minute, a self-ignition temperature of about 734.0 degrees F., andmay also merit a label of “excellence” for smoke density of a 9.3percent average.

Referring to FIGS. 6 and 7, exemplary sheet 48 may be formed of thematerials discussed with respect to FIG. 3 and further described above.Thus, sheet 48 includes a multiplicity of channels 28 defined by acooperation of members such as planar plies 22 and 24 and convoluted ply26. Sheet 48 displays first and second surfaces 50 and 52. Exemplarylayers 12 may be formed from sheet 48 by the slit-scoring technique orby the nick-scoring technique, each technique being more fully describedbelow. Alternatively, layers 12 may be formed by completely severingsheet 48 generally along lines 54. Separate layers 12 are then stackedand fixed as described above.

The slit-scoring technique is described in U.S. Pat. No. 4,803,813, theentire contents of which are hereby incorporated by reference. In theslit-scoring technique, hingelines 56 alternate with hingelines 58.Hingelines 56 are defined by extending a slit generally along a line 60and parallel (or generally transversely) to channels 28. The slitextends through planar ply 22 and convoluted ply 26, thereby leavingplanar ply 24 intact. Hingelines 58 are defined by extending a slitgenerally along a line 60 and generally parallel to hingelines 56. Theslit extends through planar ply 24 and convoluted ply 26, therebyleaving planar ply 22 intact. Intact planar plies 22 and 24 are thusused as hinges and furring strip 10 is assembled by Z-folding layers 12along hingelines 56 and 58 in the manner depicted in FIG. 7.

The nick-scoring technique is an alternative hinge-forming techniquedescribed in U.S. Pat. No. 5,094,041, the entire contents of which arehereby incorporated by reference. In the nick-scoring technique, lines60 include a series of generally linear perforations. Each perforationsubstantially extends through planar plies 22 and 24 and convoluted ply26. Substantially intact portions of planar plies 22 and 24 andconvoluted ply 26 remain between perforations. Lines 60 are thuslyformed into hinges and thereby define layers 12. Layers 12 may beZ-folded along lines 60 in a manner substantially resembling FIG. 7 toassemble furring strip 10. Still another hinge-forming techniqueincludes forming completely separated layers 12 and hingably connectingadjacent layers 12 with a pliable adhesive member such as tape.

Depicted in FIGS. 8 and 9 are embodiments of wall systems for astructure 62 according to the present invention. Structure 62 generallyincludes exterior frame wall assembly 64 and roof structure 66. Wallassembly 64 generally includes a structural frame 67 which includes soleplate 68, top plate 70, and a plurality of studs 72, with sheathing 74on the outside of structural frame 67. Sole plate 68 rests on floorassembly 76, which may be a concrete slab 78 directly on-grade asdepicted in FIG. 8, or a foundation system 80 as depicted in FIG. 9.Foundation system 80 as depicted in FIG. 9 is conventional and generallyincludes a foundation wall 82, sill plate 84, band joist 86, a pluralityof spaced-apart joists 88, and a floor membrane 90.

Studs 72 extend vertically upward connecting sole plate 68 to top plate70. Insulation 91 may be installed between studs 72. In a framestructure as depicted, studs 72 are typically the vertical structuralload bearing elements of the wall assembly 64 and may also serve assupport for sheathing 74, which in turn may serve as a portion of theouter envelope of structure 62. As previously mentioned, one or morelayers of building paper 92 may cover the exterior surface of sheathing74 to provide moisture protection and to retard air infiltration intothe interior of structure 62.

In the invention, one or more furring strips 10 may be arranged in a rowon sheathing 74 at the bottom edge 94 of wall assembly 64 to form abottom vent 96. Similarly, one or more furring strips 10 may be arrangedin a row at the top edge 98 of wall assembly 64 to form a top vent 100as depicted. Additional furring strips 10 may then be arranged to formvertical vents 102 on the sheathing 74 at spaced apart intervals so asto define a plurality of recesses 104 therebetween. Additional vents 106may be arranged around windows 108 or door 110. Alternatively, solidfurring strips may be arranged in these locations.

Finish siding 112 may be then be fastened covering furring strips 10 andsheathing 74 to form the outer surface of structure 62. Furring strips10 space finish siding 112 apart from sheathing 74, with recesses 104forming enclosed cavities 114. Air from the exterior is admitted tocavities 114 through bottom vent 96, top vent 100, and optionallythrough additional vents 106 provided around windows 108 and door 110,and may pass through vertical vents 102 so as to freely circulatebetween adjacent cavities 114 thereby promoting drying of any moisturepresent in cavities 114.

Thus, air admitted from the outdoors through bottom vent 96 or top vent100 is enabled to flow through the cavities 114 formed between thesiding 112 and the sheathing 74 over substantially all portions of wallassembly 64, promoting drying of wall assembly 64. In addition, anyliquid water present in cavities 114 is enabled to drain out throughchannels 28 in bottom vent 96.

Furring strips 10 may be fastened to sheathing 74 using any suitablefastening means, including nails, screws, adhesives, or tape. A coveredadhesive strip, such as is disclosed in U.S. Pat. No. 6,267,668, a copyof which is hereby fully incorporated herein by reference, may beprovided on a surface of furring strip 10 to facilitate installation.Generally, it is desirable to affix furring strips 10 over the wallframing members, such as studs 72, and any headers and plates, sincesiding is normally fastened to these members. Placement of furringstrips 10 over framing members and with the siding fasteners extendingtherethrough promotes stability of wall assembly 64 and may inhibitundesirable slippage and sagging of the siding 112.

It will be appreciated that the furring strips 10 of the presentinvention may be arranged in any desired pattern on the surface ofsheathing 74, as needed to promote ventilation and drainage. Forexample, furring strips 10 may be arranged primarily vertically,primarily horizontally, or in any other desired orientation.

Exemplary furring strip 10 may be about ⅝ inches in thickness and about1½ inches in width, or may be any other thickness or width dimension asmay be desirable. Furring strip 10 may be made in a variety of standardlengths, such as 92⅝″ or 96 inches, to accommodate standard wall heightdimensions, or may be made in other length dimensions and cut to lengthas needed. In addition, each furring strip 10 may be scored so as to befoldable in segments for easy handling and storage. Exemplary furringstrip 10 may be used with any type of siding including wood siding,vinyl, and metal. Also, furring strips 10 may be used to provideventilation to airspaces behind masonry structures such as brick veneer,and with suitable backing structure, spray or trowel applied finishessuch as stucco.

Although exemplary furring strips 10 have been depicted herein as usedin conjunction with frame type wall assemblies, it is contemplated thatthe present invention could be used with any type of wall constructionwherein it is desirable to provide a ventilated interstitial spacebetween wall components. In this aspect, the furring strips 10 of thepresent invention may be used, for example, with a curtain wall type ofconstruction.

Exemplary furring strip 10 of this invention thereby promotesventilation and inhibits water accumulation within wall assemblies. Theresult of installing the furring strip 10 of this invention is thusly awall, which remains drier and is more protected from decomposition anddamage than if furring strips or other devices in the prior art wereused. The furring strip of this invention will not rot, warp, or absorbwater as do many of the wooden furring strips of the prior art. Furringstrip 10 of this invention may also enable a substantial decrease intime and expense necessary to install siding as compared to solidfurring strip systems in the prior art. In contrast to wood furringstrips for example, furring strips 10 are easily cut to desired lengthswith utility knives.

1. A wall system for a structure comprising a pair of envelope layers,the pair of envelope layers being substantially coextensive and spacedapart by a plurality of furring strips, each furring strip of theplurality of furring strips defining a multiplicity of passagesextending generally transversely to a longitudinal axis of the furringstrip, the plurality of furring strips arranged so as to define aplurality of enclosed cavities between the pair of envelope layers, eachcavity being fluidly coupled to at least one adjacent cavity through thepassages in one of the plurality of furring strips.
 2. The wall systemof claim 1, wherein at least one of the pair of envelope layerscomprises sheathing.
 3. The wall system of claim 1, wherein at least oneof the pair of envelope layers comprises finish siding.
 4. The wallsystem of claim 1, wherein each furring strip includes at least onelayer comprising a generally planar first ply and a second ply, thefirst and second plies cooperating to define the multiplicity of airpassages
 5. The wall system of claim 5, wherein the second ply of eachfurring strip of the plurality of furring strips is generallyconvoluted.
 6. The wall system of claim 5, wherein each furring strip ofthe plurality of furring strips has at least a pair of first plies. 7.The wall system of claim 6, wherein the second ply of each furring stripof the plurality of furring strips includes a multiplicity ofcross-plies extending between the first plies.
 8. The wall system ofclaim 5, wherein each furring strip of the plurality of furring stripshas a plurality of layers.
 9. The wall system of claim 8, whereinadjacent layers of the plurality of layers are hingably connected at ahingeline extending generally parallel to the longitudinal axis of thefurring strip.
 10. The wall system of claim 9, wherein the hingeline ofthe furring strip is defined by a slice extending through the second plyand one of the first plies of the furring strip.
 11. The wall system ofclaim 9, wherein the furring strip has first and second hingelines, thefirst hingeline defined by a first slice extending through one of thefirst plies and the second ply, and the second hingeline defined by asecond slice extending though the other of the first plies and thesecond ply.
 12. The wall system of claim 9, wherein the hingeline of thefurring strip is defined by alternate severed and intact portions, thesevered portions comprising substantially severed first and secondplies, the intact portions comprising substantially intact first andsecond plies.
 13. The wall system of claim 8, wherein the layers of thefurring strip are stacked and fastened together.
 14. The wall system ofclaim 13, wherein the furring strip further comprises means forfastening the layers together.
 15. The wall system of claim 13, whereinthe layers of the furring strip are fastened together by stitching. 16.The wall system of claim 13, wherein the layers of the furring strip arefastened together by fasteners selected from the group consisting ofstaples, glue, hot air welding, stitching, ultrasonic welding, infraredbonding, and any combination thereof.
 17. A wall system for a structurecomprising a pair of envelope layers, the pair of envelope layers beingsubstantially coextensive and spaced apart by a plurality of elongatefurring strips, each furring strip having a pair of opposing sides, thefurring strips spaced apart so as to define a plurality of separatecavities between the pair of envelope layers, each furring strip havingmeans for fluidly coupling cavities adjacent each of the opposing sidesof the furring strip.
 18. The wall system of claim 17, wherein at leastone of the pair of envelope layers comprises sheathing.
 19. The wallsystem of claim 17, wherein at least one of the pair of envelope layerscomprises finish siding.
 20. A method of constructing an exterior wallof a building, the method comprising: providing a first generallycontinuous envelope layer, the first envelope layer presenting asurface; spacing apart a pair of elongate furring strips on the surfaceof the first envelope layer; each elongate furring strip having a pairof opposing sides and presenting a longitudinal axis, each furring stripdefining a multiplicity of passages oriented generally transverse to thelongitudinal axis and extending between the pair of opposing sides; anddisposing a second generally continuous envelope layer on the furringstrips, the second envelope layer being substantially coextensive withthe first envelope layer so as to define a cavity between the first andsecond envelope layers.
 21. A wall system for a structure comprising: afirst surface and an opposing second surface defining a cavitytherebetween; a plurality of elongate furring strips disposed in thecavity, each of the furring strips presenting a longitudinal axis anddefining a plurality of passages, the passages oriented generallytransverse to the longitudinal axis, the furring strips spaced apart inthe cavity and positioned with the longitudinal axes of the furringstrips oriented in a substantially vertical direction.
 22. The wallsystem of claim 21, wherein each furring strip comprises a pair ofgenerally planar plies spaced apart with a plurality of cross pliesextending therebetween.